EP2107662B1 - Residual current circuit breaker device - Google Patents

Abstract

The fault current protection switch unit has a total current converter (W1), through which the current conductors (1,2) are guided. Another total current converter (W2) is provided, which forms an alternative current path for the current flowing through the current conductors with reference to the former total current converter.

Description

The invention relates to a residual current circuit breaker device for the protection of persons and electrical equipment from fault currents, comprising a summation current transformer, through which the power lines are guided, which is associated with a tripping test device, and which acts on a arranged in the power line switching contact.

Devices of the type mentioned are preferably used to protect against electric shock and to protect against electrically ignited fires. Residual current protection devices of the type mentioned are known in the art. You worsen a summation current transformer through which the active current conductors to be monitored are guided. The vectorial sum of the currents in the active conductors is detected by the summation current transformer and represents a measure of the fault current. The summation current transformer is electrically subsequently arranged a trigger relay, which causes an opening of the arranged in the power lines switching contacts when a permissible residual current limit is exceeded via a switching mechanism whereby a reliable separation of a subsequent electrical system is guaranteed by the supplying power system in case of failure.

Various safety guidelines require a regular check of the function of a residual current protective device. This test is based on a tripping test device integrated in the residual current device, which simulates a fault current that causes the switching contact to function when the residual current device is functioning.

In electrical installations, sensitive consumers are frequently used where continuous operation is necessary. For these consumers, it is unacceptable that only for test purposes, the power lines are de-energized by the residual current device. In addition, in many electrical equipment after a power failure, no automatic restart is provided or permitted, so that a time-consuming initialization would be required with a restart.

An electrical bridging of a residual current device for testing purposes is inadmissible. During bridging, there is no protection for subsequent consumers.

In the prior art, therefore, the manufacturer certainly already a device of the type mentioned has already been proposed, which contains a bypass for the switching contacts of the residual current device by using a switchable contactor. The contactor forms a secondary current path, so that the switching contacts can be opened and closed without interrupting the power lines with the tripping test device. However, it must also be ensured for this case that fault current protection is developed at the moment of testing. In the known device ensuring the residual current protection during the test for proper operation of the device by means of an additional hilhspannung8abhängigen circuit is realized. Due to the use of only one summation current transformer with an associated test circuit, the proper function of the above-mentioned additional auxiliary voltage-dependent circuit can not be checked in this known device.

If a residual current of very high amplitude occurs during the self-test with the bypass closed, as in the case of a short-circuit current, there is a risk of mechanical welding of the contacts of the bypass. The known device has provided in this case additional integrated fuses, so that behind the device arranged Q: \ IB5JAW \ JAWDKA \ 2010 \ 0 \ 20100020324.doc electrical consumers are protected. However, then the known device is not usable, since the current path is permanently interrupted.

From the DE 10 2004 023 202 A1 It is known to connect a second summation current transformer via mechanical contacts to a first summation current transformer. In this connection, uncontrolled differential currents can occur, which can lead to a shutdown of the to be tested summation current transformer or the additionally added summation current transformer. A load current will unfavorably divide unevenly over both summation current transformer, so that the total current in the converter of the device to be tested is not zero and there is an unwanted tripping.

The invention has for its object to provide a device of the type mentioned, which avoids the disadvantages mentioned and which ensures a simpler means testing their function while continuing safe passage of the electrical current.

This object is achieved by the device defined in claim 1.

Particular embodiments of the invention are defined in the subclaims.

In the device according to the invention, no simulation of a current path and a residual current protection function is provided by a contactor or by other electronic, mains voltage-dependent components. Rather, in a simple manner, for example, identical summation current transformer is assigned to the first summation current transformer, the power lines are also passed through this second summation current transformer, so that virtually a double protection of the power line is given. However, this double protection makes it possible to check the functionality of one or the other summation current transformer with the aid of the test triggering device. If a switching contact is opened by a summation current transformer, then the switching contact of the second summation current transformer is still closed, so that the current can flow.

The summation current transformers and switching contacts do not require any additional mains supply. They therefore also function in the event of a power failure in the local environment of the device according to the invention.

According to the invention, it is provided that the second summation current transformer is connected in series through the current conductors to the first summation current transformer. Through this circuit, the power lines are guided in succession through both summation current transformer. This arrangement is compared to a parallel arrangement of the summation current transformer to each other the advantage that no division of the current to be tested takes place. In such a division, fault currents are already generated due to this division, which would continuously lead to a tripping of one of the two summation current transformer.

The invention further provides that the circuit breaker associated with the residual current device switch contacts are connected in parallel. This parallel switching is necessary so that each switching contact independently of the other can open or close the current path, without arranged behind the device according to the invention consumers are de-energized. The switching contacts associated with the respective unit can be configured in a simple manner so that they are both electrically and mechanically equivalent and for switching high-current electrical currents Amplitude are designed according to relevant building codes. Thus, it is also ensured that an occurring during the examination of the device according to the invention Erdkurzschlussstram with very high amplitude does not lead to welding of the contacts and the device according to the invention can continue to be used.

According to a first development of the invention, it is provided that the summation current transformer and switching contacts are arranged in one and the same housing. This housing can be made compact and accommodate all components. For a voluminous electromagnetic drive a contactor is no space vorzushalten so that this compactness can be guaranteed. Of course, the summation current transformer and associated switching contacts can also be arranged in separate housings. Thus, an MRCD (modular residual current device) can also be realized with the aid of the device according to the invention.

For further embodiment of the invention, it is also provided that at least one PTC resistor is inserted in the circuit of the tripping test devices. PTC resistors have a positive temperature coefficient which increases their resistance as the ambient temperature increases. The use of such resistors is advantageous because in the device according to the invention during intended operation according to the intended operation of the current flow to the subsequent electrical loads is not interrupted and thus the steady operation of the test button a steady flow of current through the Prüfkreiswiderstand, which possibly to a thermal overload of the Prüfkreiswiderstandes may result.

Instead of PTC resistors, however, current-regulating and thermally self-protecting electronic circuits can also be used or the number of turns of the test button winding is chosen so high that the use of typically used resistors in a small design with low power is possible even with a continuous current flow in the tripping test device ,

Another advantage of the device according to the invention is still that their components are relatively inexpensive to procure. The current transformer and switch contacts as such and also the preferred PTC resistors are inexpensive to procure and obstruct in the usual way. The device according to the invention can be designed in at least two-pole design.

To check the device according to the invention for their function, all switching contacts are initially turned on. After triggering a unit by means of associated tripping test device, it is not absolutely necessary to close the corresponding switch contacts again, since the monitoring of the power lines is always ensured by another unit. This check can advantageously be carried out equally in both units. Only when both units are in the tripped state, the power lines to be monitored are de-energized. Even if both units are switched on, there will always be a release of both units in the event of an actual fault.

A schematic diagram of the device according to the invention is shown in the drawing.

Two electric current transformers W1, W2 of the residual current circuit breaker device according to the invention are connected in series with their primary windings formed by the electrical conductors 1, 2. Each current transformer W1, W2 is electrically connected to its secondary winding with a trigger relay 18, 28. Each trigger relay 18, 28 is mechanically coupled to a switching mechanism 17, 27. Each switching mechanism 17, 27 is mechanically coupled to respectively associated switching contacts S1, S2.

Furthermore, each summation current transformer W1, W2 is still assigned a tripping test device T1, T2. Each tripping test device T1, T2 is formed by a test circuit winding 14, 24 and a test button 12, 22 and a current-determining component 13, 23.

By closing the test button 12, 22, a fault current can be simulated, which is detected by the associated summation current transformer W1, W2. The summation current transformer W1, W2 then causes an opening of the associated switching contacts S1, S2. With the switching contacts S1, S2, the current flow is interrupted via the associated power lines 1,2. A However, complete interruption of the power lines 1, 2 is only given when both switching contacts S1, S2 are open, as shown in the schematic diagram. Preferably, only one unit is switched on in the test case with the residual current circuit breaker device.

Claims (6)

1. Residual-current circuit breaker for protecting people and electrical systems from fault currents, comprising a first summation current transformer (W1), through which the current leads (1, 2) are routed and to which a tripping test device (T1) is assigned, which summation current transformer loads a first switching contact (S1) arranged in the current lead, wherein at least one second summation current transformer (W2) and at least one second switching contact (S2) are provided, and the switching contacts (S1, S2) assigned to the summation current transformers (W1, W2) are connected in parallel, and wherein the second switching contact (S2) forms a standby current path for the current flowing in the current leads with respect to the first switching contact (S1),
   characterised
   in that the second summation current transformer (W2) is connected in series by means of the current leads (1, 2) to the first summation current transformer (W1).
2. Device according to Claim 1, characterised in that the summation current transformers (W1, W2) and switching contacts (S1, S2) are arranged in one and the same housing.
3. Device according to Claim 1, characterised in that the summation current transformers (W1, W2) and the assigned switching contacts (S1, S2) are arranged in separate housings.
4. Device according to any one of the preceding claims, characterised in that at least one PTC thermistor (13) is used in the circuit of the triggering test device (T1).
5. Device according to any one of Claims 1 to 3, characterised in that a current-determining thermally self-protecting electronic circuit (13) is used in the circuit of the tripping test device (T1).
6. Device according to any one of the preceding claims, characterised in that a test circuit winding (14) has a multiplicity of windings in the circuit of the triggering test device (T1).

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